U.S. Pat. No. 1,021,984 to F. H. Holmes discloses an elevator for handling drill pipe. The device includes a dismountable strap adapted to surround the pipe beneath the coupling. The strap comprises two semiannular members hinged to each other. Bails are connected to the strap for lifting. This type of device works only with pipe provided with end couplings of a larger diameter than the pipe.
U.S. Pat. No. 3,675,278 to Thurman Powell discloses an elevator device for encircling, gripping and holding plain end well casing. The elevator includes multiple hinged frame and latch segments surrounding the pipe. The segments have wedge shaped slips on their inner diameter for gripping the pipe. Springs force the wedges into gripping contact with the pipe.
Plain end drill pipe and drill casing are commonly used today. This type of pipe and casing have threaded pin and box-ends so that radially overhanging end couplings of a larger diameter are not required. Typically plain-end type pipe and casing has parallel flat surfaces recessed into their outer diameter along secant lines at each end of the pipe. The flat surfaces provide a surface for the drill rig wrenches to grip the pipe when adding or removing pipe sections from the drill string.
It is desirable to handle plain end well drilling pipe and casing simply and reliably. The Holmes type device requires a larger diameter coupling to be on the drill pipe in order for the strap to lift it. Alternatively, some type of larger diameter member such as a lug has to be permanently or temporarily put on the drill pipe. The Powell device uses the wedging action of the slips to hold the pipe in the elevator collar. However, it is not desirable to rely on springs or latches to accomplish the gripping of a section of drill pipe since the pipe may slip from the collar when lifted.
The present invention overcomes the above shortcomings by taking advantage of the flat recessed surfaces near the ends of the drill pipe to temporarily attach a collar. The collar is axially fixed in position by the shoulders of the flat surfaces. A basket assembly with appropriate lifting bails can then be used to safely lift a section of drill pipe.